Zig-zag stitch adjusting means



Dec. 29, 1953 AMMAN 2,664,058

ZIG-ZAG STITCH ADJUSTING MEANS Filed March 28, 1951 2 Sheets-Sheet l FIG.

Inventor S g (/JIPPE Anna/v '-L 1 I r I M A g w Dec. 29, 1953 G. AMMAN 2,664,058

ZIG-ZAG STITCH ADJUSTING MEANS Filed March 28, 1951 2 Sheets-Sheet 2 Altorneys Patented Dec. 29, 1953 UNZTED STATES PATENT OFFECE ZIG-ZAG STITCH ADJUSTING MEANS Giuseppe Amman, 'Milan, Italy, assignor to Fratelli Borletti Societa per Azioni, Milan, Italy,

a body corporate 2 Claims.

In zig-zag sewing machines the movement .of oscillation of the needle is generally obtained by means of a bar, that is engaged with .one of its ends, fork-shaped, with an eccentric driven by the main shaft at one half of its own speed by means of a gear reduction, while at the .opposed end it is connected through a lever transmission to the support of the needle-carrying bar. For establishing the starting point of the osc' lation of the needle and adjusting the amplitude of said oscillation there are ordinarily employed, in the machines so arranged, two levers or knobs connected to the forked bar as before said bymeans of intermediate members.

Said levers, however, besides being located, on account of the manner in which the mechanism is constructed, in an inconvenient position for their maneuverin by the operator, and such as to spoil the aesthetics of the machine, are so ar ranged with respect to one another that a movement of one of them generally provokes an unnecessary displacement of the other one; besides, the mechanism on the whole is of a much complicated construction.

These drawbacks are eliminated by the mechanism forming the object of the present invenion.

Said mechanism, which is applicable to zig-zag sewing machi es having the needle bar actuated in a known way, by a forked bar driven by the main shaft through an ecce trio, comprises a movable guiding slot, inside of which is slidable a follower fastened to the ful rum pin of the forked bar, being connected, on one side, by means of a cross arm to a maneuvering lever apt to displace it crosswise, and on the other side, by means of a shaft co-axial with its pivot of rotation articulated at the ends so as to be susceptible of slight relative oblique and axial but not rotative displacement by means of a second maneuvering lever, that can in this way impress to it a movement of rotation around its vertical centre axis.

It is a consequence of this arran ement that, while by means of the first lever can be displaced as desired the fulcrum of oscillation of the forked bar, thus determining correspondingly the starting point of the oscillation of the needle, by

reams of a second lever can be adjusted, as needed, the amplitude of such oscillation.

The connection between the slot and the two levers is so arranged that the maneuver of each l ver is wholly independent from the movement of the other one.

According to .anotherfeature of the invention,

I'll

vention;

Fig. 2 is a detailed exploded perspective view of some elements of the mechanism;

Fig. 3 is a fragmentary diagrammatic perspective View showing a modified form of the lever actuating the oscillating support of the needle bar;

Figs. 4 to 12 represent the various positions that the actuating levers, the guiding slot and the needle bar can take for obtaining the various types of zig-sag sewing.

On shaft (Fig. 1) rotating at a speed equal to one half that of the main shaft 2 is fastened, integral therewith, eccentric The latter is em braced by the forked end 4 of a lever pivoted at 5 and connected at its opposite end S, by a connector l, to one end of a lever 8 pivoted at The other end of lever 8 is connected to a support 13 oscillating around pin H; in this support slides the needle bar 12.

Fi 3 shows the connection between lever B and support It! by means of the tzvo rrms 8 and 8' parallel to one another, of a lever pivoted on shaft 9' the function of which, analogous to the preceding one, is easily understood from Figure 3 itself. r

Pin 5, through cursor or slider 13 (Figs. 1 and 2), is held within guiding slot ill inside of which it is free to slide and turn.

An element having a guiding slot i4 is carried by a pin H: which is rotatably mounted in hole 15 in one end of movable zrm ii. The other end of arm I7 is rigidly connected to a vertical shaft 18, rotatably mounted in a hole of appendage l9 rigidly connected to the arm 22! of the machine.

At the other end of shaft 18 is rigidly connected lever 2i protruding through an opening in arm 20. By acting on lever 2 i. e. by causing it to rotate around the axis of shaft the latter is also forced to rotate, as well arm ll.

To pin 15, rotatable in hole h? is rigidly fastened socket 22 having slots 23. In said slots is positioned a cross pin 24 carried by the ball or spherical end of a shaft 25, in such a way that shaft 25 can oscillate with respect to socket 22,

but cannot turn relatively thereto, thus forming an universal joint.

A ball 26 on the other end of shaft is provided with a cross pin.

Ball 26 is mounted in a lower socket 21 similar in shape to the socket 22. Socket 2'! is machined in the end of an arm 28 rotatable on shaft 29, the latter being fixed to an appendage of arm 26 and co-axial, or simply parallel, with shaft l8.

Socket 2? can be moved around the axis of shaft 29 of the lever or handle 3|.

Shaft 25, thus, cannot rotate relative to sockets 22 and 2?, but can be subjected to oscillations and slight axial displacements relative to the sockets.

When guiding slot 14 (Figs. 1 to 6) is in a posi tion at right angles to the medium position of lever 4 i. e. to the position indicated with thin dotted lines in Fig. 5, lever 2! is in its centre position and lever 34 in the position indicated with thin dotted lines in Fig. 6. Under these conditions, lever 8 is caused to oscillate crosswise by eccentric 3 without, however, being subjected to longitudinal displacements of arm 20; the support it of the needle arm remains, consequently, stationary, an the machine can only sew a straight centre stitch as an ordinary machine.

Should it now be desired to make a zig-zag stitching with respect to the central position, in which the needle automatically and continuously displaced alternately to the right or to the left, it will be suficient to move lever from position (Fi (i) marked with thin dotted lines towards the position indicated in full lines; the amplitude of the zig-zag stitch will be greater the greater is the displacement of the lever, attaining its ma iu'm value when it will have reached the position inficated in full lines (angle a) Actually, socket 2? turns in respect to direction 32-32 and forces shaft and slot it to turn through an equal gle. Therefore, during the crosswise oscillation, accor-"ing to arrow 33 (Figs. 1 and 2) of the lever 1'5 being forced to slide within guiding s which is now inclined, lever itself will chest displacements in a direction longitudinally of the arm 28, i. e. following arrow (Fig. l) and, therefore, by the intermediary of joint and lever 8, support H1 will oscillate. Consequently also the needle bar l2 will be oscillated in a i shic-n that the needle alternately will m a stitch to the right and to the left.

According to the value of the position of lever 31, i. e., according to the value of angle a the stitch will straight, or else it will have a side amplitude, zigzag shaped, as can be seen from Fig.

Similarly, if lever 2% is in the position, all to the left, shown in Fig. 8, in which pin l5 has moved from the middle position of value a the stitches w i be all to the left and straight (Fig. 7) or else it have a side amplitude toward the right from said position proportional to the displacement a of lever 3! (Fig. 9).

And similarly, if lever 2| is in the all at the right position indicated by Fig. 11, in which the pin :5 has been displaced from the middle position of value an the stitch will be straight and all at the right (Fig. 9), or iu will have a side amplitude toward the left from said position, proportional to the displacement a of lever 31 (Fig. 2).

The working of the mechanism clearly appears from what hereinbefore described.

When a straight central stitch is wanted, lever 31 (Fig. 6) is carried to the position indicated by thin dotted lines. With lever 2| (Fig. 5) in the central position the needle will then move only up and down without any side oscillations and the stitch will be straight. If a zig-zag stitching symmetrical with the centre line is desired, it will be sufficient to act upon the lever 31 (Fig. 6).

If a straight, all to the left stitching is Wanted, lever 2| will have to be brought all to the left as indicated in Fig. 8 and lever 3i (Fig. 9) to the position shown in thin dotted lines.

If a zig-zag stitching is desired, starting from said' left hand position lever 3! will have to be brought to the left (Fig. 9) through an angle 21" proportional to the desired zig-zag amplitude.

If the straight, all to the right stitching is wanted, a similar procedure is followed (Fig. 10), but in this case lever 2| is brought over to the right as indicated in Fig. 11.

From said position at the right, a zig-zag stitching of the desired amplitude to the left is obtained by acting on lever 31 (Fig. 12).

It is understood that what has been above described represents but an example of practical construction of the object of the present invention, as constructive details can vary without exceeding the scope of said invention. Thus, for instance, the actuating levers can be brought to different position in respect to arm 29 by inserting appropriate connections between shaft l8 and lever 31 and between socket 21' and. lever 3|, respectively, and furthermore, the mechanism can be developed on horizontal rather than vertical plane, as in the example illustrated.

What I claim is:

1. In a sewing machine for zig-zag stitching having a main shaft, a reciprocating needle bar, a needle carried by said bar, a support for the needle bar and means mounting the support for oscillating movement to impart transverse oscillatory motion to the needle bar and needle, a mechanism for oscillating the needle bar support, setting the field of vibration of the needle and for regulating the amplitude of the oscillations comprising an eccentric driven by the main shaft, a lever having a forked end embracing the eccentric, and transversely oscillated thereby, means connecting the other end of the lever to said needle bar support, fulcrum means intermediate the ends of said lever, a guide element having a guiding slot therein receiving said fulcrum means, a first arm mounted for swinging movement transversely and longitudinally of the lever, means mounting said guide element on the free end of said arm for rotary movement relative to said arm about an axis parallel to the axis of the fulcrum means, a second arm mounted for swinging movement about anaxis parallel to that of the first arm, a shaft extending between the end of the second arm and the guide element, universal joint connections between said shaft and second armand between the shaft and guide element for rotating the guide element about its axis, said guide slot coacting with the fulcrum means when inclined to the path of oscillation of the fulcrum means to cause the fulcrum means to move in a direction longitudinally of the lever and impart longitudinal movement to said lever, means for shifting the second arm to shift the position of the guide element angularly about its axis to vary the longitudinal movement imparted to the lever and amplitude of the needle oscillations, and means to shift the first arm to shift the slot carrying guide element transversely and longitudinally of the lever to vary the starting point of the oscillations of the needle.

2. A mechanism according to claim 1 in which the universal joint connections each comprise a ball and socket, the socket being provided with a transverse slot, and a pin carried by the ball and sliclably engaged in the slot of the socket to enable the shaft to move axially and to be inclined relatively to said arms but insure the transmission of rotary motion from the second arm to guide element.

GIUSEPPE AMIMAN.

References Cited in the file Of this patent UNITED STATES PATENTS Number Number Name Date Tiesler Sept. 1'7, 1935 FOREIGN PATENTS Country Date Italy Sept. 17, 1938 Germany Aug. 24, 1940 

